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Titre :
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A likelihood ratio test for equality of deviations from randomness
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Auteurs :
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D. Johnson ;
A. Petkau
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Type de document :
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article/chapitre/communication
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Année de publication :
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1995
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Format :
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203-209
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Langues:
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= Anglais
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Mots-clés:
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variance-to-mean ratios
;
deviations from randomness
;
spatial pattern and counts
;
Poisson
;
negative binomial
;
Biometrie
;
Test
;
Repartition spatiale
;
Randomness
;
Loi de Poisson
;
Loi binomiale negative
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Résumé :
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The use of the sample variance-to-mean ratio as a measure of deviation front randomness in spatial pattern is reviewed. The likelihood ratio method of constructing a statistical test for the equality of several population variance-to-mean ratios is described, and details are provided for the special case where counts are modelled as arising from a negative binomial distribution. This test is illustrated by application to example data sets in ecology. Likelihood ratio tests represent a general methodology whereby relationships among several indices of aggregation can be systematically investigated, provided one is able to specify a suitable parametric form for the underlying distributions.
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Source :
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Researches on Population Ecology - 0034-5466, vol. 37, n° 2
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